New Scientist Space - 29 April 2010
Life on Mars, if it ever existed, may be easier to find than previously thought. New research on terrestrial rocks suggests that a type of rock common on Mars can preserve fossilised microbial life, rather than erasing evidence of it as previously thought.
Minerals called sulphates, which form in the presence of liquid water, have been found in great abundance on Mars, including at the landing site of NASA's Opportunity rover, Meridiani Planum.
But it has been unclear whether sulphates could preserve evidence of ancient microbial life. The rocks form when sediment compacts and crystallises, a process that – in other sedimentary rocks such as limestone – can crush the edges of microscopic fossils, destroying evidence of their existence.
Sulphate minerals like those found in Mars' Gale Crater (pictured) could
preserve evidence of past life (NASA/JPL/Arizona State University)
Earth Fossil Find May Lead to Martian Discoveries
Discovery Space News - 29 April 2010
The discovery of fossils in gypsum on Earth may help scientists zero in on fossils containing past life on Mars.
A common mineral widely believed to be a poor vessel for fossils actually contains a treasure trove of ancient life, a discovery that may lead scientists searching for life on Mars to the planet's sweet spot.
Both Earth and Mars have the mineral gypsum, though it hasn't been of much interest to scientists studying ancient life forms because no one believed tiny fossils could last in the soft, water-soluble mineral, also known as calcium sulfate.
But scientists at an astrobiology conference in Houston will report today that microscopic remnants of a diverse collection of algae and phytoplanktons have been found in samples of gypsum that formed six million years ago when the Mediterranean Sea went dry.
Hebes Chasma, located in the Grand Canyon of Mars, is one area where the mineral gypsum has been
found. New studies on Earth show gypsum can preserve fossils. (ESA/DLR/FU Berlin (G. Neukum))